Steam boiler



Jan; 17, 1933. 5, J MULLER 1,894,782

STEAM BOILER Filed Feb. 1, 1930 INVENTOR.

ATTORNEY.

Patented Jan. 17, 1933 PATENT OFFICE- GEORGE J. MULLER, F BALTIMORE, MARYLAND STEAM BOILER Application filed February 1,1930. Serial No. 425,213.

This invention has reference to an improved steam boiler and is especially designed for use in steam heating plants for domestic heating purposes, although it may readily be employed to generate steam for purposes other than heating.

In domestic heating boilers, it is desirable to provide a boiler-structure that may be operated with a comparatively small quantity of water in order that the latter may be rapidly heated to steaming temperature, and to also rid the steam of water in order that a comparatively dry steam shall be delivered to the system.

One object of the invention therefore is to provide a novel construction of boiler that may be operated on asmall quantity of water; that will rapidly generate steam, and which will operate to liberate the water car- 9 ried by the steam and cause the liberated water to return to the boiler and will also cause a circulation of water through and back to the boiler.

Another object of the invention is to provide a novel construction of boiler whose shell is of less length than the tubes therethrough and to encircle the upper ends of the tubes and shell with a drum of larger diameter than the shell and to efiect a second separation of steam from the water whereby the separated water, as well as the water that is lifted by the internal pressure in the shell, may overflow or be collected in the drum around the shell and be returned tothe boiler.

With the above, and other objects in view, the invention is diagrammatically illustrated in the drawing, wherein,-

Fig. 1 shows a form of apparatus embodying the invention, the structure being shown in vertical longitudinal section, and

Fig. 2 illustrates a crosssectional detail through the apparatus, the section being taken on the line 22 of Fig. 1.

Referring to the drawing, the numeral 5 designates an annular boiler shell having its lower end closed by a header 6, the bottom of which latter forms a lower tube-sheet 7. A fire-box 8 is located beneath said lower tube-sheet and the heating means, of any desired form, is located in this fire-box but is not shown because the means for heating is not a part of my invention.

The upper end of the annular boiler-shell is open and encircled by an annular steamdrum 9, which latter is of a larger diameter than the diameter of the boiler-shell and extends vertically from a point below to a point well above the annular edge 10 of the upper open end of the shell.

The bottom 11 of the steam-drum is therefore inturned and fits tight around the boiler shell below the upper annular edge 10 thereof so as to form an annular channel 12, on the interior between the drum-wall and the wall of the shell for the purpose of confining water boiling over the rim 10, aswill presently be explained.

The top of the drum 9 forms an upper tube sheet 13 and a large number of relatively small closely spaced fire tubes 14 extend all the way through the boiler-shell 5, and have their lower ends opening throughthe lower tube-sheet 7 while their upper ends project above the upper edge 10 of the boiler-shell andpass through the drum tube-sheet '13. The number of these tubes is large; their diameters are relatively small and they are closely spaced.

On top of the drum there is a box 15 into which the tubes open and this box therefore is the equivalent of a smoke-box and has a pipe 16 extending therefrom for products of combustion. Around the box 15, there are a plurality of pipes 17 passing through the top of the drum by means of which steam from the interior of the drum may be conveyed for utilization as a heating or other medium.

On the exterior of the annular drumfi, I provide a plurality of pipes 18. The upper ends of these pipes pass through the inturned bottom 11 of the drum, and open into the annular channel 12 around the base thereof while the lower ends of said pipes extend below the lower tube-sheet 7 and have returnbends 19 therein and then project up and enter the header 6, for the purpose of minimizing back pressure from the boiler that would oppose return of-water under the gravity head developing in the annular space 12.

In case the boiler is to be utilized in a steam-heating system, the return pipes 20 for condensate will extend to a point below the lower header or tube-sheet 7 and then project up and enter the pipes 18.

The water level in the boiler-shell is indicated by thehorizontalline 21 extending crosswise thereof and it will be noted that this Water-level line is above the point at which the condensate return-pipes 20 connect with water circulating pipes 18, therefore the water of condensation and water of circulation in pipes 18 and 20 will return jointly om the point of connection to the boiler.

During the operation of the structure, the

water in the boiler-shell will be heated and thesteam will separate therefrom and rise above the upper annular edge 10 of the shell into the drum 9.

, While the center of the drum is subject to heat from the tubes passing therethrough, the outer annular wall and the annular channel 12 around the base thereof, are subject to external atmospheric temperatures at their outer surfaces and are therefore held at a somewhat lower temperature than the cen ter of the drum. e

The water carried up by the steam from the boiler therefore separates from the steam like dew and is deposited in the annular channel 12, from which it is conveyed by the water circulating pipes 18 back through the header 6 to the boiler, and the steam passing oil through pipes 17 is comparatively dry.

In addition to this second separation of steam from the water, the first separation taking place in the boiler-shell itself, the water in the shell becomes boiling hot and boils over the upper annular edge 10 of the shell but this water, instead of bein forced into the system through the pipes f7, is directed into the annular channel 12 and returned to the boiler through a practically constant circulation through the pipes 18.

Therefore any condensate brought back b]; the pipes 20 will flow into the pipes 18 and a o be returned to the boiler.

As this circulation is practically constant, a small quantity of water only is required because any water that is blown over the edge of the boiler-shell is immediately returned to the boiler, and by providing a second separation of steam from water this additional water is also returned and the steam is discharged from the drum and started into the system in a practically dry state.

Having described my invention, I claim,

In a. steam boiler the combination with a boiler-shell open at its upper end and closed at its lower end, of a drum encircling said upper open end of the shell and extending from a point below said open end to a point above said end, a large number of relatively small closely spaced fire tubes extending through the shell and also extending through 

